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S. LBOGSDILL. mcmme m emnmmc TOOLS. MPPLICATION FILED AUG-24. I918.

Patented. Dec. 2, 1919.

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5% Wm mew 7km s. A. COG SDILL. MACHINE FOR GRINDING TOOLS. APPIQICATION FILED AUG. 24. l9l8.

Patented Dec. 2, 1919*.

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i Specification of Iletters Patent.

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Application filed August 24., 191s. Serial no. 2511225.

To all wkom'z't may concem; V

Be it known that I, STU T A. CoesDILL, a citizen of the UnitedStates of America, re siding at Detroit, in the county of Wayne 5 and State of Michigan, have invented cer-. tain new and useful Improvements inMachines for Grinding Tools, of which the foltherem to. the accompanying drawings.

This invention relates to aymachine for a grinding tools and refers more particularly to an improvedappa'ratus and method for formin combined drills and countersinks, althoug' the invention in its broaderaspects. is not necessarily limited'to the particular tools mentioned; 'f g The main object of the invention is to provide an radial relief can be "automatically givento the tool when it is. ground. Another object of the inve'utionis to prov lowing is a specification, reference being had vide an aplparatusfwhich can be used either i m origina yformi'ng the tools or regrind ing broken or injured tools. 1'1 :5 The invention also resides'in the novelarrangement for 'a greater radial reliefi to the countersin than tothedrill ,por-' tion of the tool, and in such further features of. constructionand operations as will more fully hereinafter-appear. f

In the drawings: V f 1 .I Figure 1 is a side elevational'viempartly in section, of a machine embodying my in-; vention; 1; f Fi 2 is a top plan view, 'partly'in section,

of the constructionshownin Fig. 1; Fig. 3 is an enlarged cross-section'online 33.ofF.ig.1; w p Fig. 4 is an enlarged elevational -viewlof 0 one of thetools;

Figs; 5 and 6 are enlarged detail-views of,"

- the tool. shown in Fig-. 4.-

vDescribing in detail the apparatus-shown. in the'drawmg's, A designates a tool holder-1 5 having-a chuck 13' carried bythe revoluble f shaft 0. Thelatter is mounted .in bearings Q" and O andis driven by a. suitable belt D extending over the pulley D. E designates a grinding wheel which is located in aposition 0 to, engage the tool F when the; latter is positioned within the chuck. While the form of the grinding wheel E will, ofcourse, vary with the particular tool to be operated on, it is shown as having a beveled portionE' for B grinding the countersink part F of the tool apparatus whereby the necessary wheel while the cutting edges G and a straight grinding circumference n. for grindin the drill portion I of the tool.

In certain c asses of work it is essential that the cutting portions of the tool be provided with a radial relief, that is, so formed that the distance between the rear edges G and G is less than that between the cutting edges G and G In other Words, the last mentionededgcs are formed on a part of greater diameter than the rear edges. In this way any. tendency to bind the drill point is avoided, and. it is among the chief purposes of this machineto provide a process and apparatus for automatically formin the radial relief portions when the dull 1s 70 "ground; For this purpose the work-holdin chuck B. is arranged to be given a latersfi motion at certain predetermined portions ofrotation of the work.

. As-shown in Figs. 1 and?) the bearings.

C'and C are carried by a frame H which,

at its lower end, loosely fits in a seat H in the bed plate H This frame H is pivoted to'th'e uprights H and H by pivots I and I s o*as to have a ,slight rocking movement. Secured to the shaft 0 is a ring or plate I 'which at two points in its circumference is slightly enlarged to form cam surfaces 1 At one side of'therotatable ring or plate I there is located a spring-pressed stop J ainst which the ring or plate I is pressed a w enever the cam J is rocked ,aboutits fpivot- J by the operator pressing down on the handle of the lever J9; Thus the upward movement of the cam .1" will rockv the frame H about its pivots I and I and force the stop J and compress the Thearrangeinent of parts as above described is such that as the work holder.B'95 rotates through each revolution it will, by

' the registration of the cam portions l[ with the stop J, be given a positive movement to- ,wardthe right durlng each revolution. This will carry the drill or. other tool which isbeing ground away from the grinding and G are being formed. 'As soon, however, as the cam portions I move out of engagement with the stop J, the action of the cam Jrwill rock the plate I and the frame H toward the left and thus carry the tool into closer grinding engagement with the surface E of the grinding wheel E. In this manner the portlon in the rear of the cutting edgewill be ground edges. 7

ofi deeper so as to provide the necessary radial relief.

Where combined drills and countersinks are being formed, it is often desirable that the countersink portion, because of its greater diameter, be given a greater radial This is accomplished relief than the drill. I in the same machine and by the same mecha: nism in the following manner:

In addition to the cam for rockin adjustable cams M and M which twice during each revolution register with the stationary cams L and L. The cams M- and M are carried by the wheel I or other suitable mechanism which rotates with the shaft C. The latter-is normally longitudinally withdrawn toward the left of the frame by means of the spring N, the arrangement of the shaft G rotates the cams M and M will 'come into registration with the cams L and L, forcing the work holder B and tool F toward the right. This will bring the coun tersink portion of the tool into closer grindlng engagementwith the beveled surface E and will thus grind the ortions at the rear of the cutting edges of t e countersink to a.

greater depth than the forward or cutting While I have shown and described the invention in connection with the formation of a new tool, it is obvious that broken or worn tools can be reground by the same mechanism. Also the invention is not necessarily limited to the formation of the particular kind of tool shown, and various changes can be made in the details of the apparatus for carrying out the process.

-What I claim as my invention is 1. A machine for grinding combin 'd I countersinks and drills, comprism a. grmding mechanism for. forming the dr portion of the tool and also forming the countersink portion of the tool, and means for automatithe frame H to the side, there are also emp oyed c'ally forming a'radial relief portion on said tool while being ground...

i 2. In a machine f r grmdjng tools, t.he

combination with a rotatable work-holder and means for rotatively actuating the same, of an abrasive memberfor engaging the work having faces for enga g the work both laterally and longitud-ma y, and means for shiftin the work-holder periodically both latera y and longitudinally of its. axis to vary the abrasive e ect of said-faces upon the work. Y

, 3. A machine for 'nding abrasive tools, comprising a' ivota 'frame,-a work-holder rotatively earned by said frame,

table with the work holder, means for manually swinging-said pivotal frame to aposi-v an abrasive member formed to engage the work both tion establishlng and maintaining engagement of said cam members, andcam means for periodically shifting the work-holder longltudinally of its axis of the rotation.

4. In a grinding machine, the combination with a frame, of a work holder rotatively carried by said "frame, means for rotatively actuating the work holder an abrasive memberfor engaging the work having faces for bearing both laterally and longitudinally on the work, means for periodically actuating said work holder to vary the abrasive effect upon the laterall work, and means or nally shifting the abrasive effect 11 on gaged faces of t e work.

' 5. A machine for grindin com rising an adjustable rame,-a work hol er rotatively carried "by said frame, an abrasive member sha ed to enga e the Work both laterally and ongitudina y thereof, cam members respectively stationary and roperiodically longituditatable with the work holder, means for manually actuating said frame to a position establishing and maintaining engagement of cam members, and cam means for periodically shifting the work holder longitudinally \of its axis of rotation. f

In testimony whereof I aifix m signature. STUART A.-QO SDILL.

engaged faces of the work holder to vary the the longitudinally enabrasive tools, 

